JP3175265B2 - Electromagnetic drive valve for intake and exhaust of engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetically driven valve for intake and exhaust of an engine, which is provided at an intake and exhaust port of a cylinder and is driven to open and close by an electromagnetic force.

[0002]

2. Description of the Related Art Conventionally, intake and exhaust valves arranged in a cylinder of an engine are mechanically opened and closed by a camshaft or a rocker arm driven based on rotation of a crankshaft. Since the degree of freedom of the opening and closing operation is narrow in order to synchronize with the phase, an electromagnetically driven valve for intake and exhaust of an engine has been developed in which the degree of freedom is increased by using an electromagnetic force.

As such an electromagnetic valve, there is, for example, an electromagnetic valve driving device disclosed in Japanese Patent Application Laid-Open No. Hei 3-15006 by the present applicant. In this method, a magnetic pole is provided in a valve stem, and the magnetic pole is driven by a magnetic force generated by energizing an excitation coil of a fixed magnetic pole. However, since there is an inconvenience that the weight increases due to the magnetic poles provided in the movable portion, a voice coil motor (VCM) type electromagnetic device in which a valve stem is connected to a movable coil loosely fitted to a center magnetic core like a dynamic speaker. Valves are considered.

[0004]

In the above-described valve drive mechanism having the VCM structure, the largest force is required at the time of the initial drive, and the magnetic field generated by the magnet in the field portion is not sufficiently strong.
Unless the ampere-turn of the movable coil is particularly large, there is a problem that a sufficient driving force of the electromagnetic valve cannot be obtained. The present invention has been made in view of such a problem, and an object of the present invention is to obtain a sufficient driving force by using a hybrid structure of a permanent magnet and an electromagnet in a field portion in a VCM structure valve driving mechanism. It is an object to provide an electromagnetically driven valve for intake and exhaust of an engine.

[0005]

In order to achieve the above object, according to the present invention, there is provided a valve stem which is loosely fitted in a gap between a center core and a field portion provided with a permanent magnet surrounding the outer periphery.
The energized moving coil is energized and generates a magnetic field in the air gap.
The valve stem is driven by the applied electromagnetic force.
In the electromagnetically driven valve for intake and exhaust of an engine,
Core cores with a number of core pieces
The valve stem is cylindrical, and the valve stem is inside the cylinder of the center core.
And the movable coil passes through the space at the interval from the inside.
Through a fixture having a radiating portion disposed transversely outward.
Install the permanent magnet and the center
A movable part in the cylinder axis direction in the space between
Is bonded to the center core and the outer periphery of the permanent magnet.
The outer core and the upper end of the center core and the outer core
An upper core, a lower connecting the center core and a lower end of the outer core.
And a top core adjacent to the upper end of the permanent magnet.
And a lower coil adjacent to the lower end.
I do.

[0006]

The hollow core is provided with a valve stem, and the movable coil is loosely fitted in the gap between the outer periphery of the center core and the permanent magnet. On the other hand, the field core was formed so that the upper and lower magnetic paths through the air gap were balanced, and the upper and lower coils for increasing the magnetic flux were wound around the upper and lower magnetic paths. Therefore, when the movable coil is energized, the movable coil receives the electromagnetic force generated by the magnetic field having the enhanced air gap, and strongly drives the electromagnetic valve.

[0007]

Next, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a transverse section and a longitudinal section showing one embodiment of an electromagnetically driven valve according to the present invention. In the figure, reference numeral 1 denotes an electromagnetic valve, and a valve stem 11 is supported by a valve guide 12 so as to reciprocate up and down.
Are configured to open the intake port or the exhaust port of the cylinder.

Numeral 2 designates a field core of a field portion. The upper and lower ring-shaped upper core 23 and the lower core 23 are formed above and below an annular space of a double cylindrical core composed of an outer core 21 and an inner core (center core) 22. An annular permanent magnet 3 adhered to the inner wall of the outer core 21 is attached to the annular space, and a magnetic flux in a gap between the inner wall surface of the permanent magnet 3 and the inner core 22 is formed in the annular space. The permanent magnet 3 is strongly magnetized so as to increase the density.

Reference numeral 41 denotes an upper coil, and reference numeral 42 denotes a lower coil. Each of the coils is formed in a donut shape and is disposed above and below the permanent magnet 3. An increasing current is supplied. Reference numeral 5 denotes a movable coil wound in a cylindrical shape, and is arranged so as to move up and down in the above-mentioned gap.
The electromagnetic valve 1 is a fitting 52 having a cross-shaped radiating portion 51.
The electromagnetic valve 1 is mounted above the valve stem 11 by the magnetic valve 1 and is driven by the magnetic field of the air gap and the magnetic flux of the movable coil 5 generated at the time of energization to open and close the valve.

The gap in which the movable coil 5 is arranged is formed in such a manner that the shapes of the respective cores of the field core 2 and the arrangement of the permanent magnets 3 and the upper and lower coils 41 and 42 are vertically symmetrical. Are configured so that the upper and lower magnetic paths through are substantially equal. In this way, the structure of the field
The permanent magnets 3 and the upper coils 41,
Since the arrangement of the lower coil 42 is also vertically symmetrical,
The situation is almost balanced vertically. Only
The upper coil 41 and the lower coil 42
Has become more powerful than before.
You. Then, the center stem is made cylindrical and the valve stem is
It is inserted through the inside, and as a result, the surrounding
The magnetic flux from the cylindrical permanent magnet is transferred to the outer surface of the cylinder.
Magnetic flux distribution across the air gap is uniform
And the magnetic flux that effectively links with the movable coil 5 increases.
You. The above-mentioned effects act synergistically, and in the present invention,
A large driving force can be obtained.

The inner core 22 of the field core 2 is provided with a vertical notch 221 for vertically moving the radiating portion 51 of the fixture 52, and 61 is an upper spring. , 62 are lower springs, these springs are
The valve closing position of the electromagnetic valve 1 is held by the elastic force.
It is used for the flow path to the power supply.

Next, the operation of the embodiment constructed as described above will be described. When the electromagnetic valve 1 is driven, a current of a predetermined polarity is supplied to the upper coil 41 and the lower coil 42 disposed above and below the permanent magnet 3 and the movable coil 5 is driven.
Also energize. The magnetic flux generated by the upper coil 41 and the lower coil 42 increases the magnetic flux density of the air gap formed by the permanent magnet 3. The energized movable coil 5 generates a driving force under the action of the magnetic flux in the air gap, and drives the electromagnetic valve 1 downward against the elastic force of the upper and lower springs. As a result, the valve is opened.

In the present invention, the valve stem 11 is arranged in a hollow hole of the inner core 22 of the field core 2, and the movable coil 5 is loosely fitted outside the inner core 22. Since the upper and lower coils are provided with a balance to maintain the balance between the upper and lower magnetic paths through the air gap, and the upper and lower coils are provided to increase the effective interlinkage magnetic flux, the driving force obtained by the movable coil 5 in the air gap becomes large. Therefore, the electromagnetic valve 1 is strongly driven. At the time of closing the valve, by changing the polarity of the current supplied to the movable coil 5, a driving force in the opposite direction to that described above is obtained, and the electromagnetic valve 1 is closed. As described above, the present invention has been described with the above-described embodiments. However, various modifications are possible within the scope of the gist of the present invention, and these modifications are not excluded from the scope of the present invention.

[0014]

As described above, according to the present invention, the inner core of the field core is formed in a cylindrical shape, the stem of the electromagnetic valve is arranged at the center, and a gap of the magnetic circuit is provided on the outer wall of the inner core. In addition to disposing the movable coil and maintaining the upper and lower balance of the magnetic path through the air gap, an upper coil and a lower coil are provided in these magnetic paths to increase the magnetic flux. The magnetic flux increases, the electromagnetic driving force by energizing the movable coil increases, and there is an effect that sufficient driving of the electromagnetic force can be performed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a transverse section and a longitudinal section of an electromagnetically driven valve for intake and exhaust of an engine according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electromagnetic valve, 2 ... Field core, 3 ... Permanent magnet, 5 ... Moving coil, 11 ... Valve stem, 22 ... Inner core, 41 ...
Upper coil, 42 ... Lower coil

Claims (1)

(57) [Claims] 1. A loose fit in a gap between a center core and a field portion provided with a permanent magnet surrounding an outer periphery, and attached to a valve stem.
Energized through the movable coil, which creates a magnetic field in the air gap.
The valve stem is driven by the generated electromagnetic force.
In the electromagnetically driven valve for intake and exhaust of an engine, the center core is formed by standing a plurality of core pieces at intervals.
The valve stem is inserted into a cylinder of the center core, and the movable coil traverses the space of the interval from inside to outside.
The valve stay is connected via a fixture having a radiating portion
To the space between the permanent magnet and the center core.
The field portion is disposed in the gap so as to be movable in the cylindrical axis direction, and the field portion is in contact with the center core and the outer periphery of the permanent magnet.
The attached outer core, the center core and the upper end of the outer core
The upper core to be connected, and the lower ends of the center core and the outer core to each other.
An upper coil is provided adjacent to the upper end of the permanent magnet.
Characterized in that a lower coil is provided adjacent to the
An electromagnetically driven valve for intake and exhaust.